Let's say you're at work and you find a document that shows your company has been giving out misleading information. Or, let's say you see a co-worker act in an abusive or unethical manner. Would you speak up? Well, social scientists have been asking why whistle-blowers become whistle-blowers.

NPR's Shankar Vedantam has been checking out their work. And he joins us, as he often does, to talk about interesting social science research. Shankar, welcome back.

SHANKAR VEDANTAM, BYLINE: Hi, David.

GREENE: So, you know, we kind of think of whistleblowers when they emerge as big heroes. And I guess there is question: Why aren't there more of them?

VEDANTAM: You know, David, that might be part of the problem. There are these two big theories on why people step forward to report problems. The first is that they are heroes. They always do the right thing. And the management textbooks say it's all about ethical leadership, because when someone reports a problem it's up to managers to either ignore the problem or to act on it.

I spoke with David Mayer. He's a researcher at the University of Michigan. And along with his colleagues, he decided to test these theories. He looked at survey data involving more than 30,000 Americans. And he looked at how often people report seeing or hearing violations of their companies' code of conduct. And astonishingly he found that as many as one-in-five people reported seeing these kinds of violations. But remarkably, only half of the people spoke up and said anything about it.

Mayer told me that he dug a little bit deeper. And he found that what made the difference was not whether people had ethical leadership.

DAVID MAYER: What we've neglected is understanding better the role of people who are not in formal positions of power - our peers. If we don't get consistent support from our coworkers, we're much less likely to act.

GREENE: OK. So, Shankar, what they say is that the assumption was that you take, kind of, ethical cues from bosses. He seems to be saying that we're actually taking cues from our coworkers.

VEDANTAM: That's right, David. He's finding that the effects of having an ethical supervisor are completely neutralized, if people felt their peers were unethical. So when people felt they had ethical peers they reported problems. When they felt that coworkers were unethical they were much less likely to speak up.

GREENE: Is the data really clear on this? I mean couldn't there be other things going on? It just strikes me as taking a leap to say that if my peers or unethical, I'm going to make an unethical decision and not report something.

VEDANTAM: Mayer told me he had the same questions. He wanted proof. And so, he decided to conduct this experiment involving about a hundred adults. He asked them to come up with a solution to a problem. He sat them down at a computer. And told them they were going to be working with others, working at other computers. If the team as a whole got the answer right, there would be this big $300 cash prize.

But they were not allowed to go on the Internet and get any information that could help them solve the problem. As soon as the volunteers sat down at the computer, he or she got an instant message from one of the coworkers. At the coworkers said, Hey, guess what - I figured out I could use my iPhone to go on the Internet...

(LAUGHTER)

GREENE: Sneaky.

VEDANTAM: ...and get the information that we need. Now, here comes the experimental manipulation. For some of the volunteers, Mayer had the other coworkers act in an ethical fashion. They said, Look, this isn't right - we are breaking the rules. But for some of the volunteers he had the coworkers act unethically. They said, Great, I wish I had thought of that - I'm sure we're going to win the cash price now.

And the experimental question was: Would the volunteers themselves report the problem afterwards to the researcher. And what he found was when the coworkers were ethical, two-thirds of the volunteers reported that there was a problem. When the coworkers were unethical, only one-third of the volunteers spoke up.

And Mayer it's prompted him to rethink the very way in which human beings make moral decisions.

MAYER: About 20 to 25 percent of people just tend to do the right thing, regardless of the environment. And then I think maybe we get 10 to 20 percent who might just be a little bit more likely to do that self-interested thing. And then the majority of us follow in this area in the middle. And I would say really good people, who fall in this area in the middle, but are just heavily influenced by their environment.

GREENE: Well, I mean this is interesting because we, sort of, think of ourselves as making up our own moral minds. But it sounds like that it might be, in some ways, less about who we are as individuals and sometimes more about the environment.

VEDANTAM: You know, David, many of us buy the idea that it takes a village to act ethically. I think what Mayer's experiment show is that it also takes a village to act unethically.

GREENE: Interesting stuff. Shankar, thanks for coming in as always.

VEDANTAM: Thanks, David.

GREENE: Shankar Vedantam, who regularly joins us to talk about interesting social science research he's come across. You can follow him on Twitter @hiddenbrain and, while you're at it, you can follow this program @nprgreene, @nprinskeep and @morningedition. Transcript provided by NPR, Copyright NPR.